Clay,
Adding a GPS Receiver like the GP320 will not improve the VX2 7" Display's target clarity, but it will provide the display with Position. And if you add a GPS Receiver and Heading Sensor it will then allow you to overlay the Radar on to the Plotter Screen.
The only thing that will increase a Radar's Target Clarity is a having sharper beam width Antenna when using an Open Array Antenna instead of a Dome/Assy. The longer the Array the the tighter the beam width with more energy being focused on targets, resulting in better target resolution.
I hope you find this information useful..?
-Deep Blue :cool